Methyl trifluoroacetate along with cesium fluoride or cesium chloride and CuI constitutes a valuable trifluoromethylating reagent for substituting aromatic (or heteroaromatic) iodides and bromides. Adsorption of methyl trifluoroacetate on amorphous silica has been investigated. Fragmentation mechanism of generation of metastable ions from methyl trifluoroacetate has been investigated by mass analyzed ion kinetic energy spectra and ab initio molecular orbital calculations.